function ideal(){
	var clHight = document.documentElement.clientHeight
	var iDeal = document.getElementsByClassName('introduce-left')
	var aAn = document.getElementsByClassName('an')
	document.onscroll = function(){
		for(index = 0;index < aAn.length; index++){
			var al = aAn[index];
			if(al.getBoundingClientRect().top < clHight){
				al.classList.add('animated')
				al.classList.add('bounceInLeft')
			}
		}
		
		
}
ideal()